The present invention relates generally to new and useful devices and methods of packaging food products, and more specifically, to improved tubular casing brake or sizing devices for food stuffing apparatus.
In the manufacture of sausage products, a tubular food casing, such as cellulose is loaded onto the stuffing horn of a filling machine and stuffed with an emulsion, usually comprised of comminuted meat together with fillers, seasonings, spices, etc. In the case of small sausage products, like frankfurters, the filled casings are twisted, tied, or clipped into suitable links at predetermined intervals and further processed.
For larger diameter sausage products, like bolognas, salamis, and the like, the meat emulsion is introduced into larger, heavier walled fibrous type casings or casings formed from thermoplastic films and formed into chubs or lengthy individual sticks. Like the smaller products, these large diameter sausage products are filled on stuffing machines comprising a meat pump and a delivery attachment in the form of a stuffing horn. However, unlike small diameter products, larger type sausage products, such as bologna, packaged in large code casings rely on heavy duty end-closures in the form of metal clips or caps and frequently tied with a looped string, twine or other equivalent means attached, all for securely containing the meat emulsion during the stuffing process and for suspending the product during further processing, e.g., cooking and smoking, storage and display. U.S. Pat. No. 4,165,593 is one example of cut lengths of casing closed at one end with a clip for securing a loop for suspending the sausage product. The casing, end-closure clip and loop are manufactured in a first operation and later fitted onto the horn of a filling machine by meat processors in an independent operation where it is filled and closed at the second end.
In stuffing large diameter casings a sizing or braking system can be employed for controlling casing expansion to avoid exceeding casing manufacturers recommended stuffing diameters while also preventing back "purge" of meat emulsion. This is achieved with a brake device which applies uniform pressure to the exterior wall of unfilled casing on a stuffing horn as emulsion fills the casing interior. The braking device, which may comprise a ring assembly engages the casing restricting its rate of withdrawal from the horn by regulating drag generated by friction. Representative brake systems are disclosed by U.S. Pat. Nos. 3,748,690 (Niedecker); 3,621,513 (Kupcikevicius); 3,457,588 (Myles et al); 4,438,545 (Kupcikevicius et al) and 4,558,488 (Martinek), to name but a few.
In most brake/sizing systems force is applied uniformly and circumferentially (360.degree.) to the outer casing wall by compression against the stuffing horn, etc. The stuffing cycle typically begins with the operator loading a precut length of casing onto the stuffing horn with the first end of the casing having a tied or clipped end-closure and a looped string attached thereto. The closed, first end of the casing is flush with the outlet end of the horn which horn is then indexed and aligned with the brake ring opening. The brake ring assembly is advanced so the loaded horn is coaxial with the brake ring engaging the casing against the horn closest to the outlet end. Frequently, however, in the process the looped string hanging from the clipped or capped end-closure or string tied casings become "locked" between the brake ring and casing side wall. Consequently, unless the string is released before stuffing is initiated casing is unable to peel off the horn, pressure builds up quickly at the outlet end of the horn causing the casing to rupture. This means costly down time for cleanup, lost meat emulsion in the work area, lost production and wasted casings.
Accordingly, the present invention contemplates improved sizing/braking devices for food stuffing apparatus for filling string tied/looped casing while significantly reducing snagging and consequent casing rupture. This translates into important economic advantages through higher production efficiencies with less down time.
A further important consideration in preparation of large diameter sausage products is the maintenance of accurate size control over the entire length of the sausage stick. It is particularly important that the diameter of the large sausage products be carefully controlled so that meat packers are able to cut the sausage into slices of predetermined thickness and diameter for prepackaging. The objective is to have a given number of slices weigh precisely a predetermined amount for each package. As a result, meat processors are constantly striving to improve operations that affect finished package yields. Constant sizing control during stuffing of green stick diameter assures more uniform slice weight and minimizes package over and under weight variations.
U.S. Pat. Nos. 3,748,690 and 3,872,543 to Niedecker disclose popular style sizing devices for controlling product diameter. During filling, controlled release of casing is achieved by a snubbing element bearing against the outlet end of the stuffing horn with the casing therebetween. It has been found, however, that the outlet end of stuffing horns can be fragile and subject to bending and loss of cylindrical shape unless specially reinforced. Because of distortion in roundness of horn outlets snubbing rings, particularly those which operate by engaging the edge of stuffing horns, such as disclosed by the Niedecker patents can fail to provide accurate product diameter control during filling operations.
Although snubbing lips of devices like those of Niedecker are fabricated from essentially resilient materials they are nevertheless made relatively rigid and nonflexible due to steel backing members exerting pressure thereon. Consequently, desired flexibility and resiliency of such devices ar lost at the point of constriction of casing against the filling horn making it difficult for irregular shaped folds in casing to smoothly negotiate constriction points without producing deviations in constant pressures and ultimately variations in product diameter. Rigid steel holders for such devices also shorten the useful life expectancy of these sizing rings due to excess wear.
Accordingly, the present invention also contemplates improved flexibility and longer wearing sizing devices which offer a high degree of dimensional uniformity and caliber control without dependence on horn roundness and cylindrical shape for optimum size control during stuffing, and without casing wall thickness interfering with sizing ring performance.